A network called a body area network is known as a wireless network formed on a human body. The IEEE committee standardizes the body area network, and IEEE 802.15.6 specifications are established. In the body area network, a hub as a central device and a node as a terminal device are mounted in the human body, and communication is performed between the hub and the node, for example.
An access scheme of IEEE 802.15.6 uses a mechanism of temporally sharing a TDMA (Time Division Multiple Access)-based access scheme and a CSMA (Carrier Sense Multiple Access)-based or slot ALOHA-based access scheme on the same frequency.
Meanwhile, a mechanism of separately providing a control channel and a data channel and using the CSMA-based access scheme in the channels is examined as an access technique for supporting asynchronous ad hoc communication. However, all control frames are transmitted and received through the control channel, and it is essential that the hub and the node always monitor the control channel at timing other than data transmission and reception through the data channel.
An access scheme using a plurality of control channels and data channels is also examined, and transmission of the same beacon signal at the same timing in all channels is stipulated.
In this way, the conventional IEEE 802.15.6 system uses the mechanism of temporally sharing a plurality of access schemes on the same frequency, and there is a problem that the power consumption is large due to the complexity of the system. In the two access techniques using the control channel and the data channel, both of the hub and the node basically need to always monitor both of the channels or at least the control channel, and there is a problem in terms of the power consumption.